The present disclosure relates to an endoscope.
In a medical field and an industrial field, endoscopes are widely used for various inspections. Endoscopes for medical use have a flexible elongated insertion section having a distal end provided with a solid state image sensor, and the insertion section is inserted into a subject such as a patient to acquire an in-vivo image in a body cavity of the subject without incision, and further to treat the subject using a treatment instrument projecting from the distal end of the insertion section if necessary. Thus, the endoscopes have been widely used.
In such an endoscope, a diameter of the insertion section is required to be reduced. As a technique to reduce a size of the insertion section, an imaging device is provided in which a circuit board having an image sensor mounted thereon, and a signal cable connected thereto includes a plurality of layers, a minor axis of the circuit board and a radius of the endoscope are disposed to be parallel in direction, and the layered circuit board has a width reduced toward an outer periphery of the endoscope to have a stepped form. Such an imaging device preventing interference with a case at the distal end of the endoscope, and reducing the diameter of the endoscope is disclosed (e.g., see JP 2012-147968 A).
There is a need for an endoscope achieving reduction in diameter of an insertion section storing an imaging device and a built-in component.